Survey of energy efficient tracking and localization techniques in buildings using optical and wireless communication media

This paper presents a survey of beamforming, beamsteering and mobile tracking techniques. The survey was made in the context of the SOWICI project. The aim of this project is to reduce power consumption of data exchanging devices within houses. An optical fiber network is used for data transport to and from rooms whereas wireless transceivers communicate with appliances within the rooms. Using this approach, the aim is to reduce power consumption and exposure to electromagnetic radiation. To realize this, beamforming will be used to only radiate energy in, and receive signals from, the direction of interest. Because appliances within households can move, some of them even relatively fast, the pointing direction of the beam should be steerable. The pointing direction can be deduced from the communication link (beamsteering) or via separate mobile tracking techniques

Sabrewing: a lightweight architecture for combined floating-point and integer arithmetic

In spite of the fact that floating-point arithmetic is costly in terms of silicon area, the joint design of hardware for floating-point and integer arithmetic is seldom considered. While components like multipliers and adders can potentially be shared, floating-point and integer units in contemporary processors are practically disjoint. This work presents a new architecture which tightly integrates floating-point and integer arithmetic in a single datapath. It is mainly intended for use in low-power embedded digital signal processors and therefore the following design constraints were important: limited use of pipelining for the convenience of the compiler; maintaining compatibility with existing technology; minimal area and power consumption for applicability in embedded systems. The architecture is tailored to digital signal processing by combining floating-point fused multiply-add and integer multiply-accumulate. It could be deployed in a multi-core system-on-chip designed to support applications with and without dominance of floating-point calculations. The VHDL structural description of this architecture is available for download under BSD license. Besides being configurable at design time, it has been thoroughly checked for IEEE-754 compliance by means of a floating-point test suite originating from the IBM Research Labs. A proof-of-concept has also been implemented using STMicroelectronics 65nm technology. This prototype supports 32-bit signed two’s complement integers and 41-bit (8-bit exponent and 32-bit significand) floating-point numbers. Our evaluations show that over 67% energy and 19% area can be saved compared to a reference design in which floating-point and integer arithmetic are implemented separately. The area overhead caused by combining floating-point and integer is less than 5%. Implemented in ST’s general-purpose CMOS technology, the design can operate at a frequency of 1.35GHz, while 667MHz can be achieved in low-power CMOS. Considering that the entire datapath is partitioned in just three pipeline stages, and the fact that the design is intended for use in the low-power domain, these frequencies are adequate. They are in fact competitive with current technology low-power floating-point units. Post-layout estimates indicate that the required area of a low-power implementation can be as small as 0.04mm2 . Power consumption is on the order of several milliwatts. Strengthened by the fact that clock gating could reduce power consumption even further, we think that a shared floating-point and integer architecture is a good choice for signal processing in low-power embedded systems

Interim report on the Southeast Queensland Cloud Seeding Research Program

Water stresses are occurring in Southeast Queensland. In order to assess the feasibility of any future precipitation enhancement potential in clouds in the Southeast Queensland region, it is extremely important to obtain observations in a well-designed measurement program. Aerosol and microphysical measurements, in particular, can help determine if seeding could be beneficial and also help determine what the optimal seeding method would be with regards to potential for enhancing precipitation in local clouds. The potential for such manmade increases is strongly dependent on the natural microphysics and dynamics of the clouds that are being seeded (in this case microphysics means the size and concentration of water droplets and ice inside clouds). These factors can differ significantly from one geographical region to another, as well as during and between seasons in the same region. In some instances, clouds may not be suitable for seeding, or the frequency of occurrence of suitable clouds may be too low to warrant the investment in a cloud seeding program. Both factors need to be evaluated from a climatological perspective. It is therefore important to conduct preliminary studies on the microphysics and dynamics of the naturally forming clouds prior to commencing a larger, operational experiment. It is also important to conduct hydrological studies relating rainfall with river flows and reservoir levels, and to determine hydrological regions where reservoir catchments are most efficient. Seeding could then be optimized by preferentially targeting the most efficient watersheds. The following is a summary of key preliminary results derived from the analysis of data collected during the 2007-2008 season in Southeast Queensland

Survey of energy efficient tracking and localization techniques in buildings using optical and wireless communication media

This paper presents a survey of beamforming, beamsteering and mobile tracking techniques. The survey was made in the context of the SOWICI project. The aim of this project is to reduce power consumption of data exchanging devices within houses. An optical fiber network is used for data transport to and from rooms whereas wireless transceivers communicate with appliances within the rooms. Using this approach, the aim is to reduce power consumption and exposure to electromagnetic radiation. To realize this, beamforming will be used to only radiate energy in, and receive signals from, the direction of interest. Because appliances within households can move, some of them even relatively fast, the pointing direction of the beam should be steerable. The pointing direction can be deduced from the communication link (beamsteering) or via separate mobile tracking techniques